Motor-driven tool



Aug. 8, 1944. H. E. MELTZER MOTOR DRIVEN TOOL Filed Aug. 4, 1941 INVENTOR ATToR'NEYs HENRY EMELTZER' Patented Aug. 8, 1944 UNITED STATES PATENT OFFICE y MOTOR-DItIVEN TOOL Henry E. Meltzer, Racine, Wis.

Application August 4, 1941, Serial No. 405,455'

4 Claims. (Cl. 279-52) This invention pertains generally to electrically driven tools, and more particularly to portable hand tools.

In conventional tools of the foregoing type `provided with a tool chuck mounted upon the armature shaft of the motor, difficulty has been lencountered in clamping the chuck because of the free rotation of the motor shaft. To overcomethe foregoing objection, several forms' of locking devices have been devised to lock the armature shaft against rotation while manipulating the chuck. 1

However, as far as is known, such locking de- 'vices comprise depressible plungers actuated which avoids any lateral strain upon the shaft.

Incidental to the foregoing, a more specic object of the invention resides in the provision of a depressible locking mechanism carried by the chuck and longitudinally moveable with rela tion to the armature shaft for locking the shaft and chuck against rotation.

With the above and other objects in view, which will appear as the description proceeds, the invention resides in the novel construction, combination and arrangement of parts, substantially as hereinafter describecLand more particularly dened by the appended claims, it being understood that such changes in the precise embodiment of the herein disclosed invention may be made as come within the scope of the claims.

In the accompanying drawing is illustrated one complete example of the physical embodiment of the present invention constructed according to the best mode so far devised for the practical application of the principles thereof.

In the drawing:

Figure 1 is a fragmentary elevationof an electric hand tool incorporating the present invention, parts being broken away in sections to more clearly illustrate structural details.

Figure 2 is a similar view.

Figure 3 is a detail elevational view of the chuck and locking mechanism;

Figure 4 is the transverse sectional view taken down the line 4-4 of Figure 3;

"lo the outer end of the recessed boss 8, as shown in Figure 5 is similar view takenon `the line 5-,5 of Figure 1; and f 1 Figure 6 is a transverse sectional view taken out of the line 6-6 of Figure l. y

Referring now more particularly to the accompanying drawing, the numeral l designates a casing consisting of an inner metallic sleeve 2, surrounded by an outer plastic shell 3.

Housed within the casing is a conventional electric vmotor 4 having an. armature shaft 5, which is journaled at itsforward end in a bearing 6, carried by a head 'I secured within` the end of the metallic sleeve 2.

The outer end of the head I is provided with a recessed boss 8 for reception of the shank 9 of the tool chuck, the outer end of the shank being slotted, and exteriorally threaded to receive a tapered cap I0, which serves to clamp the shank of a tool I I within the chuck.

The shank 9 of the chuck is secured to the armature shaft 5 by a set screw`l2, as best shown in Figure 6, while the rear end of the shank is journaled within a recess I3 formed in the head l. The boss 8 is provided with a tool opening 8' to facilitate the adjustment of the set screw I2.

Adjacent its inner end the chuck shank 9 is provided with a flange I4 located within the recessed boss 8 and provided with a plurality of radially spaced openings I5 for alignment with pockets I6 formed in the head 6.

Slidably mounted upon the other end of the shank 9 is a disc I'I, to which a plurality of pins I8 are secured, the ends of the pins extending into the openings I5 in the chuck Iiange I 4, as best shown in Figure 1. A coil spring I9 is disposed between the flange I4 and the disc I'I and the spring functions to normally hold the disc I'I against the chuck cap I0.

In its normal position the disc II is ush with Figures 1 and 2, and in order to facilitate depression of the disc the recessed boss 8 is pro--` vided with oppositely disposed cut out portions 20.

In operation, when it is desired to manipulate the', chuck cap I0 for removal or insertion of the tool II, the operator merely depresses the disc I'I with his nger to project the pins I8 into the pockets I6 formed in the head 6, thus locking the chuck shank 9 and the armature shaft 5 against rotation as the chuck cap I0 is turned on the shank 9.

To facilitate locking of the chuck and armature shaft the recessed boss 6 is provided with an indicia I l', which enables the operator to properly align the pins I8 for projection into the pockets From the foregoing explanation considered in connection with the accompanying drawing, it will be seen that an exceedingly simple and compact mechanism has been provided for locking the armature shaft of a motor driven tool against rotation during manipulation of the tool chuck, and at the same time there are no lateral projections such as plungers t interfere with manipulation of the tool, or allow unintentional locking of the shaft while the motor is in operation.

It will also be appreciated that the present invention serves to lock the chuck shank, and consequently motor shaft at a plurality of radially spaced points, thus securely holding the shaft against lateral springing in the event of undue force being exerted upon the chuck cap by means of wrenches or other tools.

I claim:

1. In a motorI driven tool including a casing, a head secured to one end of theV casing, a rotatable shank having a tool chuckiextending beyond said head, a manually depressible disc non-rotatably mounted on said chuck andA longitudinally movable thereon said head having keepery openings therein, and annularly spaced pins carried by said disc for engagementl in the keeper openings in said head, when the sleeve is in one of its: positions for locking said chuck and casing head against relative rotary movement. i

2. In a motor driven. tool including a casing, a head secured to one end of the casing, a rotatable shank having a tool chuck extending beyond said head, said chuck including a locking cap, a manually depressible disc non-rotatably mounted on said chuck and longitudinally movable thereon, said head having keeper openings therein, annularly spaced pins carried by said disc for engagement in the keeper 'openings in said head when the sleeveis in oneof its positionsv for lockthe openings in the head. Y

ing said chuck and casing head against relative rotary movement, and spring means normally holding the disc against said cap and the pins out of locking engagement with the head.

3. In a motor driven tool including a casing, a head secured to one end of the casing provided with an outwardly extending hollow boss, a rotatable shank having a tool chuck rotatable in said hollow boss and with the forward end thereof extending beyond said hollow-boss, a manually depressible disc non-rotatably mounted on said chuck and disposed within said hollow boss for movement longitudinally of the chuck and boss, said head having keeper openings therein, and annularly spaced pins carried by said disc for engagement vin said keeper openings in said head when the disc is in one of its positions for lock Aing said chuckand casing head against relative with provided with openings therethrough for '.alinement with the openings in the head, a manually depressible disc slidably mounted on said chuck, annularly spaced pins carried by said disc slidably mounted inthe openings in the ange and movable into Vthe openings in the head when said disc is moved toward the flange, and a spring `coiled about said chuck and disposed between thel flange and discV for normally holding the disc away from the flange and thepins out yof HENRY E. MELTZER. 

